[Swift] 음양 더하기

 

import Foundation

func solution(_ absolutes:[Int], _ signs:[Bool]) -> Int {
    
    var count:Int = 0
    var result:Int = 0
    
    for input in signs {
        if input == true {
            result += absolutes[count]
        } else {
            result -= absolutes[count]
        }
        count += 1
    }
    
    
    return result
}

 

 

1) 두 배열을 튜플로 만들기

import Foundation

func solution(_ absolutes:[Int], _ signs:[Bool]) -> Int {
    zip(absolutes, signs)
    
	//signs의 값에 따라 수(abslutes)가 변한다 -> 배열로 들어감
        .map { $1 ? $0 : -$0 }
        //줄여서 더한다
        .reduce(0, +)
}

 

Function

zip(_:_:)

Creates a sequence of pairs built out of two underlying sequences.

 

 

 

 

If the two sequences passed to zip(_:_:) are different lengths, the resulting sequence is the same length as the shorter sequence. In this example, the resulting array is the same length as words:

let naturalNumbers = 1...Int.max
let zipped = Array(zip(words, naturalNumbers))
// zipped == [("one", 1), ("two", 2), ("three", 3), ("four", 4)]

 

 

map(_:)

Returns an array containing the results of mapping the given closure over the sequence’s elements.

let cast = ["Vivien", "Marlon", "Kim", "Karl"]
let lowercaseNames = cast.map { $0.lowercased() }
// 'lowercaseNames' == ["vivien", "marlon", "kim", "karl"]​